ychen updated this revision to Diff 371221.
ychen added a comment.
Herald added a subscriber: jdoerfert.
- Use more specific diagnoses "left operand of comma operator has no effect"
when left operand of comma operator has no effect instead of "expression
result is unused".
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D103938/new/
https://reviews.llvm.org/D103938
Files:
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/include/clang/Sema/Sema.h
clang/lib/Sema/SemaExpr.cpp
clang/lib/Sema/SemaExprCXX.cpp
clang/lib/Sema/SemaStmt.cpp
clang/test/Analysis/dead-stores.c
clang/test/CXX/basic/basic.link/p8.cpp
clang/test/CXX/drs/dr14xx.cpp
clang/test/CXX/drs/dr20xx.cpp
clang/test/CXX/drs/dr7xx.cpp
clang/test/CXX/temp/temp.constr/temp.constr.constr/partial-specializations.cpp
clang/test/CodeCompletion/pragma-macro-token-caching.c
clang/test/Frontend/fixed_point_crash.c
clang/test/PCH/cxx-explicit-specifier.cpp
clang/test/Parser/cxx-ambig-decl-expr.cpp
clang/test/Parser/cxx0x-ambig.cpp
clang/test/Parser/cxx1z-init-statement.cpp
clang/test/Parser/objc-messaging-1.m
clang/test/Parser/objc-try-catch-1.m
clang/test/Parser/objcxx11-attributes.mm
clang/test/Sema/const-eval.c
clang/test/Sema/exprs.c
clang/test/Sema/i-c-e.c
clang/test/Sema/sizeless-1.c
clang/test/Sema/switch-1.c
clang/test/Sema/vla-2.c
clang/test/Sema/warn-type-safety.c
clang/test/Sema/warn-unused-value.c
clang/test/SemaCXX/attr-annotate.cpp
clang/test/SemaCXX/builtin-constant-p.cpp
clang/test/SemaCXX/constant-expression-cxx2a.cpp
clang/test/SemaCXX/constant-expression.cpp
clang/test/SemaCXX/expression-traits.cpp
clang/test/SemaCXX/matrix-type-operators.cpp
clang/test/SemaCXX/overloaded-operator.cpp
clang/test/SemaCXX/sizeless-1.cpp
clang/test/SemaCXX/vector.cpp
clang/test/SemaCXX/warn-comma-operator.cpp
clang/test/SemaCXX/warn-unused-value.cpp
clang/test/SemaTemplate/derived.cpp
clang/test/SemaTemplate/lambda-capture-pack.cpp
Index: clang/test/SemaTemplate/lambda-capture-pack.cpp
===================================================================
--- clang/test/SemaTemplate/lambda-capture-pack.cpp
+++ clang/test/SemaTemplate/lambda-capture-pack.cpp
@@ -18,7 +18,7 @@
namespace PR41576 {
template <class... Xs> constexpr int f(Xs ...xs) {
return [&](auto ...ys) { // expected-note {{instantiation}}
- return ((xs + ys), ...); // expected-warning {{unused}}
+ return ((xs + ys), ...); // expected-warning {{left operand of comma operator has no effect}}
}(1, 2);
}
static_assert(f(3, 4) == 6); // expected-note {{instantiation}}
Index: clang/test/SemaTemplate/derived.cpp
===================================================================
--- clang/test/SemaTemplate/derived.cpp
+++ clang/test/SemaTemplate/derived.cpp
@@ -49,6 +49,6 @@
class A {
TFP m_p;
- void Enable() { 0, A(); } // expected-warning {{unused}}
+ void Enable() { 0, A(); } // expected-warning {{left operand of comma operator has no effect}}
};
}
Index: clang/test/SemaCXX/warn-unused-value.cpp
===================================================================
--- clang/test/SemaCXX/warn-unused-value.cpp
+++ clang/test/SemaCXX/warn-unused-value.cpp
@@ -1,6 +1,7 @@
// RUN: %clang_cc1 -fsyntax-only -verify -Wunused-value %s
// RUN: %clang_cc1 -fsyntax-only -verify -Wunused-value -std=c++98 %s
// RUN: %clang_cc1 -fsyntax-only -verify -Wunused-value -std=c++11 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -Wunused-value -std=c++17 %s
// PR4806
namespace test0 {
@@ -138,3 +139,26 @@
(void)arr3;
(void)arr4;
}
+
+#if __cplusplus >= 201103L // C++11 or later
+namespace test5 {
+int v[(5, 6)]; // expected-warning {{left operand of comma operator has no effect}}
+void foo() {
+ new double[false ? (1, 2) : 3]
+ // FIXME: We shouldn't diagnose the unreachable constant expression
+ // here.
+ [false ? (1, 2) : 3]; // expected-warning {{left operand of comma operator has no effect}}
+}
+} // namespace test5
+#endif
+
+#if __cplusplus >= 201703L // C++11 or later
+namespace test6 {
+auto b() {
+ if constexpr (false)
+ return (1,0);
+ else
+ return (1.0,0.0); // expected-warning {{left operand of comma operator has no effect}}
+}
+} // namespace test6
+#endif
Index: clang/test/SemaCXX/warn-comma-operator.cpp
===================================================================
--- clang/test/SemaCXX/warn-comma-operator.cpp
+++ clang/test/SemaCXX/warn-comma-operator.cpp
@@ -242,8 +242,8 @@
template <typename... xs>
class Foo {
- typedef bool_seq<(xs::value, true)...> all_true;
- typedef bool_seq<(xs::value, false)...> all_false;
+ typedef bool_seq<((void)xs::value, true)...> all_true;
+ typedef bool_seq<((void)xs::value, false)...> all_false;
typedef bool_seq<xs::value...> seq;
};
Index: clang/test/SemaCXX/vector.cpp
===================================================================
--- clang/test/SemaCXX/vector.cpp
+++ clang/test/SemaCXX/vector.cpp
@@ -381,8 +381,8 @@
typedef int inte2 __attribute__((__ext_vector_type__(2)));
void test_vector_literal(inte4 res) {
- inte2 a = (inte2)(1, 2); //expected-warning{{expression result unused}}
- inte4 b = (inte4)(a, a); //expected-error{{C-style cast from vector 'inte2' (vector of 2 'int' values) to vector 'inte4' (vector of 4 'int' values) of different size}} //expected-warning{{expression result unused}}
+ inte2 a = (inte2)(1, 2); //expected-warning{{left operand of comma operator has no effect}}
+ inte4 b = (inte4)(a, a); //expected-error{{C-style cast from vector 'inte2' (vector of 2 'int' values) to vector 'inte4' (vector of 4 'int' values) of different size}} //expected-warning{{left operand of comma operator has no effect}}
}
typedef __attribute__((__ext_vector_type__(4))) float vector_float4;
Index: clang/test/SemaCXX/sizeless-1.cpp
===================================================================
--- clang/test/SemaCXX/sizeless-1.cpp
+++ clang/test/SemaCXX/sizeless-1.cpp
@@ -85,9 +85,9 @@
(void)local_int8;
- local_int8, 0; // expected-warning + {{expression result unused}}
+ local_int8, 0; // expected-warning {{left operand of comma operator has no effect}}
- 0, local_int8; // expected-warning + {{expression result unused}}
+ 0, local_int8; // expected-warning {{left operand of comma operator has no effect}} expected-warning {{expression result unused}}
svint8_t init_int8 = local_int8;
svint8_t bad_init_int8 = for; // expected-error {{expected expression}}
Index: clang/test/SemaCXX/overloaded-operator.cpp
===================================================================
--- clang/test/SemaCXX/overloaded-operator.cpp
+++ clang/test/SemaCXX/overloaded-operator.cpp
@@ -157,7 +157,7 @@
void test_comma(X x, Y y) {
bool& b1 = (x, y);
- X& xr = (x, x); // expected-warning {{expression result unused}}
+ X& xr = (x, x); // expected-warning {{left operand of comma operator has no effect}}
}
struct Callable {
Index: clang/test/SemaCXX/matrix-type-operators.cpp
===================================================================
--- clang/test/SemaCXX/matrix-type-operators.cpp
+++ clang/test/SemaCXX/matrix-type-operators.cpp
@@ -179,12 +179,12 @@
a[4, 5] = 5.0;
// expected-error@-1 {{comma expressions are not allowed as indices in matrix subscript expressions}}
- // expected-warning@-2 {{expression result unused}}
+ // expected-warning@-2 {{left operand of comma operator has no effect}}
a[4, 5, 4] = 5.0;
// expected-error@-1 {{comma expressions are not allowed as indices in matrix subscript expressions}}
- // expected-warning@-2 {{expression result unused}}
- // expected-warning@-3 {{expression result unused}}
+ // expected-warning@-2 {{left operand of comma operator has no effect}}
+ // expected-warning@-3 {{left operand of comma operator has no effect}}
}
void extract(sx5x10_t a, float f) {
Index: clang/test/SemaCXX/expression-traits.cpp
===================================================================
--- clang/test/SemaCXX/expression-traits.cpp
+++ clang/test/SemaCXX/expression-traits.cpp
@@ -583,10 +583,10 @@
// Can't use the ASSERT_XXXX macros without adding parens around
// the comma expression.
- static_assert(__is_lvalue_expr(x,x), "expected an lvalue");
- static_assert(__is_rvalue_expr(x,1), "expected an rvalue");
- static_assert(__is_lvalue_expr(1,x), "expected an lvalue");
- static_assert(__is_rvalue_expr(1,1), "expected an rvalue");
+ static_assert(__is_lvalue_expr((void)x,x), "expected an lvalue");
+ static_assert(__is_rvalue_expr((void)x,1), "expected an rvalue");
+ static_assert(__is_lvalue_expr((void)1,x), "expected an lvalue");
+ static_assert(__is_rvalue_expr((void)1,1), "expected an rvalue");
}
#if 0
Index: clang/test/SemaCXX/constant-expression.cpp
===================================================================
--- clang/test/SemaCXX/constant-expression.cpp
+++ clang/test/SemaCXX/constant-expression.cpp
@@ -88,8 +88,8 @@
void diags(int n) {
switch (n) {
- case (1/0, 1): // expected-error {{not an integral constant expression}} expected-note {{division by zero}}
- case (int)(1/0, 2.0): // expected-error {{not an integral constant expression}} expected-note {{division by zero}}
+ case (1/0, 1): // expected-error {{not an integral constant expression}} expected-note {{division by zero}} expected-warning {{left operand of comma operator has no effect}}
+ case (int)(1/0, 2.0): // expected-error {{not an integral constant expression}} expected-note {{division by zero}} expected-warning {{left operand of comma operator has no effect}}
case __imag(1/0): // expected-error {{not an integral constant expression}} expected-note {{division by zero}}
case (int)__imag((double)(1/0)): // expected-error {{not an integral constant expression}} expected-note {{division by zero}}
;
Index: clang/test/SemaCXX/constant-expression-cxx2a.cpp
===================================================================
--- clang/test/SemaCXX/constant-expression-cxx2a.cpp
+++ clang/test/SemaCXX/constant-expression-cxx2a.cpp
@@ -745,7 +745,7 @@
// Ensure that we can handle temporary cleanups for array temporaries.
struct ArrElem { constexpr ~ArrElem() {} };
using Arr = ArrElem[3];
- static_assert((Arr{}, true));
+ static_assert(((void)Arr{}, true));
}
namespace dynamic_alloc {
Index: clang/test/SemaCXX/builtin-constant-p.cpp
===================================================================
--- clang/test/SemaCXX/builtin-constant-p.cpp
+++ clang/test/SemaCXX/builtin-constant-p.cpp
@@ -157,12 +157,12 @@
constexpr ~A() { *p = 0; }
};
struct Q { int n; constexpr int *get() { return &n; } };
- static_assert(!__builtin_constant_p((A{}, 123)));
+ static_assert(!__builtin_constant_p(((void)A{}, 123)));
// FIXME: We should probably accept this. GCC does.
// However, GCC appears to do so by running the destructors at the end of the
// enclosing full-expression, which seems broken; running them at the end of
// the evaluation of the __builtin_constant_p argument would be more
// defensible.
- static_assert(!__builtin_constant_p((A{Q().get()}, 123)));
+ static_assert(!__builtin_constant_p(((void)A{Q().get()}, 123)));
}
#endif
Index: clang/test/SemaCXX/attr-annotate.cpp
===================================================================
--- clang/test/SemaCXX/attr-annotate.cpp
+++ clang/test/SemaCXX/attr-annotate.cpp
@@ -42,7 +42,7 @@
template<typename T>
struct B {
- [[clang::annotate("test", (T{}, 9))]] void t() {}
+ [[clang::annotate("test", ((void)T{}, 9))]] void t() {}
// expected-error@-1 {{illegal initializer type 'void'}}
};
B<int> b;
@@ -73,7 +73,7 @@
[[clang::annotate("jui", b, cf)]] void t2() {}
// expected-error@-1 {{'annotate' attribute requires parameter 1 to be a constant expression}}
// expected-note@-2 {{is not allowed in a constant expression}}
- [[clang::annotate("jui", (b, 0), cf)]] [[clang::annotate("jui", &b, cf, &foo::t2, str())]] void t3() {}
+ [[clang::annotate("jui", ((void)b, 0), cf)]] [[clang::annotate("jui", &b, cf, &foo::t2, str())]] void t3() {}
};
};
Index: clang/test/Sema/warn-unused-value.c
===================================================================
--- clang/test/Sema/warn-unused-value.c
+++ clang/test/Sema/warn-unused-value.c
@@ -9,31 +9,31 @@
// PR4806
void pr4806() {
- 1,foo(); // expected-warning {{expression result unused}}
+ 1,foo(); // expected-warning {{left operand of comma operator has no effect}}
// other
foo();
i; // expected-warning {{expression result unused}}
- i,foo(); // expected-warning {{expression result unused}}
+ i,foo(); // expected-warning {{left operand of comma operator has no effect}}
foo(),i; // expected-warning {{expression result unused}}
- i,j,foo(); // expected-warning {{expression result unused}} expected-warning {{expression result unused}}
- i,foo(),j; // expected-warning {{expression result unused}} expected-warning {{expression result unused}}
- foo(),i,j; // expected-warning {{expression result unused}} expected-warning {{expression result unused}}
+ i,j,foo(); // expected-warning 2{{left operand of comma operator has no effect}}
+ i,foo(),j; // expected-warning {{left operand of comma operator has no effect}} expected-warning {{expression result unused}}
+ foo(),i,j; // expected-warning {{expression result unused}} expected-warning {{left operand of comma operator has no effect}}
i++;
i++,foo();
foo(),i++;
- i++,j,foo(); // expected-warning {{expression result unused}}
+ i++,j,foo(); // expected-warning {{left operand of comma operator has no effect}}
i++,foo(),j; // expected-warning {{expression result unused}}
foo(),i++,j; // expected-warning {{expression result unused}}
- i,j++,foo(); // expected-warning {{expression result unused}}
- i,foo(),j++; // expected-warning {{expression result unused}}
- foo(),i,j++; // expected-warning {{expression result unused}}
+ i,j++,foo(); // expected-warning {{left operand of comma operator has no effect}}
+ i,foo(),j++; // expected-warning {{left operand of comma operator has no effect}}
+ foo(),i,j++; // expected-warning {{left operand of comma operator has no effect}}
i++,j++,foo();
i++,foo(),j++;
@@ -86,7 +86,7 @@
void f0(int a);
void f1(struct s0 *a) {
// rdar://8139785
- f0((int)(a->f0 + 1, 10)); // expected-warning {{expression result unused}}
+ f0((int)(a->f0 + 1, 10)); // expected-warning {{left operand of comma operator has no effect}}
}
void blah(int a);
Index: clang/test/Sema/warn-type-safety.c
===================================================================
--- clang/test/Sema/warn-type-safety.c
+++ clang/test/Sema/warn-type-safety.c
@@ -145,7 +145,7 @@
void test_tag_expresssion(int b) {
fcntl(0, b ? F_DUPFD : F_SETLK, 10); // no-warning
fcntl(0, b + F_DUPFD, 10); // no-warning
- fcntl(0, (b, F_DUPFD), 10); // expected-warning {{expression result unused}}
+ fcntl(0, (b, F_DUPFD), 10); // expected-warning {{left operand of comma operator has no effect}}
}
// Check that using 64-bit magic values as tags works and tag values do not
Index: clang/test/Sema/vla-2.c
===================================================================
--- clang/test/Sema/vla-2.c
+++ clang/test/Sema/vla-2.c
@@ -4,14 +4,14 @@
// a different codepath when we have already emitted an error.)
int PotentiallyEvaluatedSizeofWarn(int n) {
- return (int)sizeof *(0 << 32,(int(*)[n])0); // expected-warning {{expression result unused}} expected-warning {{shift count >= width of type}}
+ return (int)sizeof *(0 << 32,(int(*)[n])0); // expected-warning {{left operand of comma operator has no effect}} expected-warning {{shift count >= width of type}}
}
void PotentiallyEvaluatedTypeofWarn(int n) {
- __typeof(*(0 << 32,(int(*)[n])0)) x; // expected-warning {{expression result unused}} expected-warning {{shift count >= width of type}}
+ __typeof(*(0 << 32,(int(*)[n])0)) x; // expected-warning {{left operand of comma operator has no effect}} expected-warning {{shift count >= width of type}}
(void)x;
}
void PotentiallyEvaluatedArrayBoundWarn(int n) {
- (void)*(int(*)[(0 << 32,n)])0; // FIXME: We should warn here.
+ (void)*(int(*)[(0 << 32,n)])0; // expected-warning {{left operand of comma operator has no effect}}
}
Index: clang/test/Sema/switch-1.c
===================================================================
--- clang/test/Sema/switch-1.c
+++ clang/test/Sema/switch-1.c
@@ -50,7 +50,7 @@
return 0;
}
return (i, 65537) * 65537; // expected-warning {{overflow in expression; result is 131073 with type 'int'}} \
- // expected-warning {{expression result unused}}
+ // expected-warning {{left operand of comma operator has no effect}}
}
// rdar://18405357
Index: clang/test/Sema/sizeless-1.c
===================================================================
--- clang/test/Sema/sizeless-1.c
+++ clang/test/Sema/sizeless-1.c
@@ -76,9 +76,9 @@
(void)local_int8;
- local_int8, 0; // expected-warning + {{expression result unused}}
+ local_int8, 0; // expected-warning {{left operand of comma operator has no effect}}
- 0, local_int8; // expected-warning + {{expression result unused}}
+ 0, local_int8; // expected-warning {{left operand of comma operator has no effect}} expected-warning {{expression result unused}}
svint8_t init_int8 = local_int8;
svint8_t bad_init_int8 = for; // expected-error {{expected expression}}
Index: clang/test/Sema/i-c-e.c
===================================================================
--- clang/test/Sema/i-c-e.c
+++ clang/test/Sema/i-c-e.c
@@ -70,10 +70,12 @@
char z[__builtin_constant_p(4) ? 1 : -1];
// Comma tests
-int comma1[0?1,2:3];
-int comma2[1||(1,2)]; // expected-warning {{use of logical '||' with constant operand}} \
- // expected-note {{use '|' for a bitwise operation}}
-int comma3[(1,2)]; // expected-warning {{variable length array folded to constant array as an extension}}
+int comma1[0?1,2:3]; // expected-warning {{left operand of comma operator has no effect}}
+int comma2[1 || (1, 2)]; // expected-warning {{use of logical '||' with constant operand}} \
+ // expected-note {{use '|' for a bitwise operation}} \
+ // expected-warning {{left operand of comma operator has no effect}}
+int comma3[(1, 2)]; // expected-warning {{variable length array folded to constant array as an extension}} \
+ // expected-warning {{left operand of comma operator has no effect}}
// Pointer + __builtin_constant_p
char pbcp[__builtin_constant_p(4) ? (intptr_t)&expr : 0]; // expected-error {{variable length array declaration not allowed at file scope}}
Index: clang/test/Sema/exprs.c
===================================================================
--- clang/test/Sema/exprs.c
+++ clang/test/Sema/exprs.c
@@ -13,10 +13,9 @@
// Test that we don't report divide-by-zero errors in unreachable code.
-// This test should be left as is, as it also tests CFG functionality.
void radar9171946() {
if (0) {
- 0 / (0 ? 1 : 0); // expected-warning {{expression result unused}}
+ 0 / (0 ? 1 : 0); // no-warning
}
}
Index: clang/test/Sema/const-eval.c
===================================================================
--- clang/test/Sema/const-eval.c
+++ clang/test/Sema/const-eval.c
@@ -74,7 +74,7 @@
EVAL_EXPR(35, constbool)
EVAL_EXPR(36, constbool)
-EVAL_EXPR(37, (1,2.0) == 2.0 ? 1 : -1)
+EVAL_EXPR(37, ((void)1,2.0) == 2.0 ? 1 : -1)
EVAL_EXPR(38, __builtin_expect(1,1) == 1 ? 1 : -1)
// PR7884
Index: clang/test/Parser/objcxx11-attributes.mm
===================================================================
--- clang/test/Parser/objcxx11-attributes.mm
+++ clang/test/Parser/objcxx11-attributes.mm
@@ -22,7 +22,7 @@
// A message send which contains a message send is OK.
[ [ X alloc ] init ];
- [ [ int(), noreturn getSelf ] getSize ]; // expected-warning {{unused}}
+ [ [ int(), noreturn getSelf ] getSize ]; // expected-warning {{left operand of comma operator has no effect}}
// A message send which contains a lambda is OK.
[ [noreturn] { return noreturn; } () setSize: 4 ];
Index: clang/test/Parser/objc-try-catch-1.m
===================================================================
--- clang/test/Parser/objc-try-catch-1.m
+++ clang/test/Parser/objc-try-catch-1.m
@@ -28,14 +28,13 @@
}
@catch (Frob* ex) {
@throw 1,2; // expected-error {{@throw requires an Objective-C object type ('int' invalid)}} \
- // expected-warning {{expression result unused}}
+ // expected-warning {{left operand of comma operator has no effect}}
}
@catch (float x) { // expected-error {{@catch parameter is not a pointer to an interface type}}
}
@catch(...) {
- @throw (4,3,proc()); // expected-warning {{expression result unused}} \
- // expected-warning {{expression result unused}}
+ @throw (4,3,proc()); // expected-warning 2{{left operand of comma operator has no effect}}
}
}
Index: clang/test/Parser/objc-messaging-1.m
===================================================================
--- clang/test/Parser/objc-messaging-1.m
+++ clang/test/Parser/objc-messaging-1.m
@@ -7,20 +7,20 @@
[a ii]; // expected-warning{{not found}}
[a if: 1 :2]; // expected-warning{{not found}}
[a inout: 1 :2 another:(2,3,4)]; // expected-warning{{not found}} \
- // expected-warning 2{{expression result unused}}
+ // expected-warning 2{{left operand of comma operator has no effect}}
[a inout: 1 :2 another:(2,3,4), 6,6,8]; // expected-warning{{not found}} \
- // expected-warning 2{{expression result unused}}
+ // expected-warning 2{{left operand of comma operator has no effect}}
[a inout: 1 :2 another:(2,3,4), (6,4,5),6,8]; // expected-warning{{not found}} \
- // expected-warning 4{{expression result unused}}
+ // expected-warning 4{{left operand of comma operator has no effect}}
[a inout: 1 :2 another:(i+10), (i,j-1,5),6,8]; // expected-warning{{not found}} \
- // expected-warning 2{{expression result unused}}
+ // expected-warning 2{{left operand of comma operator has no effect}}
[a long: 1 :2 another:(i+10), (i,j-1,5),6,8]; // expected-warning{{not found}} \
- // expected-warning 2{{expression result unused}}
+ // expected-warning 2{{left operand of comma operator has no effect}}
[a : "Hello\n" :2 another:(i+10), (i,j-1,5),6,8]; // expected-warning{{not found}} \
- // expected-warning 2{{expression result unused}}
+ // expected-warning 2{{left operand of comma operator has no effect}}
// Comma expression as receiver (rdar://6222856)
[a, b, c foo]; // expected-warning{{not found}} \
- // expected-warning 2{{expression result unused}}
+ // expected-warning 2{{left operand of comma operator has no effect}}
}
Index: clang/test/Parser/cxx1z-init-statement.cpp
===================================================================
--- clang/test/Parser/cxx1z-init-statement.cpp
+++ clang/test/Parser/cxx1z-init-statement.cpp
@@ -14,8 +14,8 @@
// init-statement expressions
if (T{f()}; f()) {} // expected-warning {{expression result unused}}
- if (T{f()}, g, h; f()) {} // expected-warning 2{{unused}} expected-warning {{expression result unused}}
- if (T(f()), g, h + 1; f()) {} // expected-warning 2{{unused}} expected-warning {{expression result unused}}
+ if (T{f()}, g, h; f()) {} // expected-warning 2{{left operand of comma operator has no effect}} expected-warning {{expression result unused}}
+ if (T(f()), g, h + 1; f()) {} // expected-warning 2{{left operand of comma operator has no effect}} expected-warning {{expression result unused}}
// condition declarations
if (T(n){g}) {}
@@ -26,8 +26,8 @@
// condition expressions
if (T(f())) {}
if (T{f()}) {}
- if (T(f()), g, h) {} // expected-warning 2{{unused}}
- if (T{f()}, g, h) {} // expected-warning 2{{unused}}
+ if (T(f()), g, h) {} // expected-warning 2{{left operand of comma operator has no effect}}
+ if (T{f()}, g, h) {} // expected-warning 2{{left operand of comma operator has no effect}}
// none of the above, disambiguated as expression (can't be a declaration)
if (T(n)(g)) {} // expected-error {{undeclared identifier 'n'}}
Index: clang/test/Parser/cxx0x-ambig.cpp
===================================================================
--- clang/test/Parser/cxx0x-ambig.cpp
+++ clang/test/Parser/cxx0x-ambig.cpp
@@ -163,7 +163,7 @@
(void)p1;
UnsignedTmplArgSink<T(CtorSink(t ...)) ...> *t0; // ok
- UnsignedTmplArgSink<((T *)0, 42u) ...> **t0p = &t0;
+ UnsignedTmplArgSink<((T *)0, 42u) ...> **t0p = &t0; // expected-warning 2{{left operand of comma operator has no effect}}
}
template void foo(int, int, int); // expected-note {{in instantiation of function template specialization 'ellipsis::foo<int, int>' requested here}}
Index: clang/test/Parser/cxx-ambig-decl-expr.cpp
===================================================================
--- clang/test/Parser/cxx-ambig-decl-expr.cpp
+++ clang/test/Parser/cxx-ambig-decl-expr.cpp
@@ -24,7 +24,7 @@
// This is array indexing not an array declarator because a comma expression
// is not syntactically a constant-expression.
- int(x[1,1]); // expected-warning 2{{unused}}
+ int(x[1,1]); // expected-warning {{left operand of comma operator has no effect}} expected-warning {{unused}}
// This is array indexing not an array declaration because a braced-init-list
// is not syntactically a constant-expression.
@@ -36,8 +36,8 @@
int(a[{0}]); // expected-warning {{unused}}
// These are array declarations.
- int(x[(1,1)]); // expected-error {{redefinition}}
- int(x[true ? 1,1 : 1]); // expected-error {{redefinition}}
+ int(x[((void)1,1)]); // expected-error {{redefinition}}
+ int(x[true ? 1 : (1,1)]); // expected-error {{redefinition}} // expected-warning {{left operand of comma operator has no effect}}
int (*_Atomic atomic_ptr_to_int);
*atomic_ptr_to_int = 42;
Index: clang/test/PCH/cxx-explicit-specifier.cpp
===================================================================
--- clang/test/PCH/cxx-explicit-specifier.cpp
+++ clang/test/PCH/cxx-explicit-specifier.cpp
@@ -12,7 +12,7 @@
template<typename X, typename Y> struct T {
template<typename A>
- explicit((Y{}, true)) T(A &&a) {}
+ explicit(((void)Y{}, true)) T(A &&a) {}
};
template<typename X, typename Y> struct U : T<X, Y> {
@@ -28,7 +28,7 @@
U<S, char> a = foo('0');
}
-//CHECK: explicit((char{} , true))
+//CHECK: explicit(((void)char{} , true))
#endif
Index: clang/test/Frontend/fixed_point_crash.c
===================================================================
--- clang/test/Frontend/fixed_point_crash.c
+++ clang/test/Frontend/fixed_point_crash.c
@@ -14,7 +14,7 @@
int fn2() {
union a m;
m.x = 7, 5.6k; // expected-warning {{expression result unused}}
- return m.x, m.i; // expected-warning {{expression result unused}}
+ return m.x, m.i; // expected-warning {{left operand of comma operator has no effect}}
}
-_Accum acc = (0.5r, 6.9k); // expected-warning {{expression result unused}}
+_Accum acc = (0.5r, 6.9k); // expected-warning {{left operand of comma operator has no effect}}
Index: clang/test/CodeCompletion/pragma-macro-token-caching.c
===================================================================
--- clang/test/CodeCompletion/pragma-macro-token-caching.c
+++ clang/test/CodeCompletion/pragma-macro-token-caching.c
@@ -12,7 +12,7 @@
void completeParamPragmaError(int param) {
Outer(__extension__({ _Pragma(2) })); // expected-error {{_Pragma takes a parenthesized string literal}}
- param; // expected-warning {{expression result unused}}
+ param;
}
// RUN: %clang_cc1 -fsyntax-only -verify -code-completion-at=%s:16:1 %s | FileCheck %s
Index: clang/test/CXX/temp/temp.constr/temp.constr.constr/partial-specializations.cpp
===================================================================
--- clang/test/CXX/temp/temp.constr/temp.constr.constr/partial-specializations.cpp
+++ clang/test/CXX/temp/temp.constr/temp.constr.constr/partial-specializations.cpp
@@ -26,7 +26,7 @@
template<typename T> requires (T{}) // expected-error{{atomic constraint must be of type 'bool' (found 'int')}}
struct B<T**> {};
- static_assert((B<int**>{}, true)); // expected-note{{while checking constraint satisfaction for class template partial specialization 'B<int *>' required here}}
+ static_assert(((void)B<int**>{}, true)); // expected-note{{while checking constraint satisfaction for class template partial specialization 'B<int *>' required here}}
// expected-note@-1{{while checking constraint satisfaction for class template partial specialization 'B<int>' required here}}
// expected-note@-2{{during template argument deduction for class template partial specialization 'B<T *>' [with T = int *]}}
// expected-note@-3{{during template argument deduction for class template partial specialization 'B<T **>' [with T = int]}}
Index: clang/test/CXX/drs/dr7xx.cpp
===================================================================
--- clang/test/CXX/drs/dr7xx.cpp
+++ clang/test/CXX/drs/dr7xx.cpp
@@ -26,12 +26,12 @@
use(a);
use((a));
use(cond ? a : a);
- use((cond, a)); // expected-warning 2{{unused}} FIXME: should only warn once
+ use((cond, a)); // expected-warning 2{{left operand of comma operator has no effect}} FIXME: should only warn once
(void)a; // FIXME: expected-error {{declared in enclosing}}
(void)(a); // FIXME: expected-error {{declared in enclosing}}
(void)(cond ? a : a); // FIXME: expected-error 2{{declared in enclosing}}
- (void)(cond, a); // FIXME: expected-error {{declared in enclosing}} expected-warning {{unused}}
+ (void)(cond, a); // FIXME: expected-error {{declared in enclosing}} expected-warning {{left operand of comma operator has no effect}}
}
};
}
Index: clang/test/CXX/drs/dr20xx.cpp
===================================================================
--- clang/test/CXX/drs/dr20xx.cpp
+++ clang/test/CXX/drs/dr20xx.cpp
@@ -221,7 +221,7 @@
a.*&A::x; // expected-warning {{unused}}
true ? a.x : a.y; // expected-warning {{unused}}
(void)a.x;
- a.x, discarded_lval(); // expected-warning {{unused}}
+ a.x, discarded_lval(); // expected-warning {{left operand of comma operator has no effect}}
#if 1 // FIXME: These errors are all incorrect; the above code is valid.
// expected-error@-6 {{enclosing function}}
// expected-error@-6 {{enclosing function}}
Index: clang/test/CXX/drs/dr14xx.cpp
===================================================================
--- clang/test/CXX/drs/dr14xx.cpp
+++ clang/test/CXX/drs/dr14xx.cpp
@@ -18,7 +18,7 @@
Check<true ? 0 : A::unknown_spec>::type *var1; // expected-error {{undeclared identifier 'var1'}}
Check<true ? 0 : a>::type *var2; // ok, variable declaration expected-note 0+{{here}}
Check<true ? 0 : b>::type *var3; // expected-error {{undeclared identifier 'var3'}}
- Check<true ? 0 : (c, 0)>::type *var4; // expected-error {{undeclared identifier 'var4'}}
+ Check<true ? 0 : ((void)c, 0)>::type *var4; // expected-error {{undeclared identifier 'var4'}}
// value-dependent because of the implied type-dependent 'this->', not because of 'd'
Check<true ? 0 : (d(), 0)>::type *var5; // expected-error {{undeclared identifier 'var5'}}
// value-dependent because of the value-dependent '&' operator, not because of 'A::d'
Index: clang/test/CXX/basic/basic.link/p8.cpp
===================================================================
--- clang/test/CXX/basic/basic.link/p8.cpp
+++ clang/test/CXX/basic/basic.link/p8.cpp
@@ -27,7 +27,7 @@
void linkage2f(Linkage2);
void use_linkage() {
- &linkage1v, &linkage1iv, &linkage2v, &linkage2iv, &linkaget1v; // expected-warning 5{{unused}}
+ &linkage1v, &linkage1iv, &linkage2v, &linkage2iv, &linkaget1v; // expected-warning 4{{left operand of comma operator has no effect}} expected-warning {{unused}}
linkage1f();
linkage2f({});
}
Index: clang/test/Analysis/dead-stores.c
===================================================================
--- clang/test/Analysis/dead-stores.c
+++ clang/test/Analysis/dead-stores.c
@@ -339,12 +339,12 @@
(void)(0 && x);
(void)y7;
(void)(0 || (y8, ({ return; }), 1));
- // non-nested-warning@-1 {{expression result unused}}
+ // non-nested-warning@-1 {{left operand of comma operator has no effect}}
(void)x;
break;
case 8:
(void)(1 && (y9, ({ return; }), 1));
- // non-nested-warning@-1 {{expression result unused}}
+ // non-nested-warning@-1 {{left operand of comma operator has no effect}}
(void)x;
break;
case 9:
Index: clang/lib/Sema/SemaStmt.cpp
===================================================================
--- clang/lib/Sema/SemaStmt.cpp
+++ clang/lib/Sema/SemaStmt.cpp
@@ -216,9 +216,9 @@
return S.Diag(Loc, diag::warn_unused_result_msg) << A << Msg << R1 << R2;
}
-void Sema::DiagnoseUnusedExprResult(const Stmt *S) {
+void Sema::DiagnoseUnusedExprResult(const Stmt *S, unsigned DiagID) {
if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S))
- return DiagnoseUnusedExprResult(Label->getSubStmt());
+ return DiagnoseUnusedExprResult(Label->getSubStmt(), DiagID);
const Expr *E = dyn_cast_or_null<Expr>(S);
if (!E)
@@ -264,7 +264,6 @@
// Okay, we have an unused result. Depending on what the base expression is,
// we might want to make a more specific diagnostic. Check for one of these
// cases now.
- unsigned DiagID = diag::warn_unused_expr;
if (const FullExpr *Temps = dyn_cast<FullExpr>(E))
E = Temps->getSubExpr();
if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E))
@@ -339,7 +338,7 @@
if (LangOpts.OpenMP && isa<CallExpr>(Source) &&
POE->getNumSemanticExprs() == 1 &&
isa<CallExpr>(POE->getSemanticExpr(0)))
- return DiagnoseUnusedExprResult(POE->getSemanticExpr(0));
+ return DiagnoseUnusedExprResult(POE->getSemanticExpr(0), DiagID);
if (isa<ObjCSubscriptRefExpr>(Source))
DiagID = diag::warn_unused_container_subscript_expr;
else
@@ -379,7 +378,8 @@
return;
}
- DiagRuntimeBehavior(Loc, nullptr, PDiag(DiagID) << R1 << R2);
+ DiagIfReachable(Loc, S ? llvm::makeArrayRef(S) : llvm::None,
+ PDiag(DiagID) << R1 << R2);
}
void Sema::ActOnStartOfCompoundStmt(bool IsStmtExpr) {
Index: clang/lib/Sema/SemaExprCXX.cpp
===================================================================
--- clang/lib/Sema/SemaExprCXX.cpp
+++ clang/lib/Sema/SemaExprCXX.cpp
@@ -8524,7 +8524,7 @@
if (FullExpr.isInvalid())
return ExprError();
- DiagnoseUnusedExprResult(FullExpr.get());
+ DiagnoseUnusedExprResult(FullExpr.get(), diag::warn_unused_expr);
}
FullExpr = CorrectDelayedTyposInExpr(FullExpr.get(), /*InitDecl=*/nullptr,
Index: clang/lib/Sema/SemaExpr.cpp
===================================================================
--- clang/lib/Sema/SemaExpr.cpp
+++ clang/lib/Sema/SemaExpr.cpp
@@ -28,6 +28,7 @@
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/AST/TypeLoc.h"
#include "clang/Basic/Builtins.h"
+#include "clang/Basic/DiagnosticSema.h"
#include "clang/Basic/PartialDiagnostic.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
@@ -13369,7 +13370,7 @@
if (LHS.isInvalid())
return QualType();
- S.DiagnoseUnusedExprResult(LHS.get());
+ S.DiagnoseUnusedExprResult(LHS.get(), diag::warn_unused_comma_left_operand);
if (!S.getLangOpts().CPlusPlus) {
RHS = S.DefaultFunctionArrayLvalueConversion(RHS.get());
@@ -18896,6 +18897,37 @@
EvaluatedExprMarker(*this, SkipLocalVariables).Visit(E);
}
+/// Emit a diagnostic when statements are reachable.
+/// FIXME: check for reachability even in expressions for which we don't build a
+/// CFG (eg, in the initializer of a global or in a constant expression).
+/// For example,
+/// namespace { auto *p = new double[3][false ? (1, 2) : 3]; }
+bool Sema::DiagIfReachable(SourceLocation Loc, ArrayRef<const Stmt *> Stmts,
+ const PartialDiagnostic &PD) {
+ if (!Stmts.empty() && !FunctionScopes.empty()) {
+ FunctionScopes.back()->PossiblyUnreachableDiags.push_back(
+ sema::PossiblyUnreachableDiag(PD, Loc, Stmts));
+ return true;
+ }
+
+ // The initializer of a constexpr variable or of the first declaration of a
+ // static data member is not syntactically a constant evaluated constant,
+ // but nonetheless is always required to be a constant expression, so we
+ // can skip diagnosing.
+ // FIXME: Using the mangling context here is a hack.
+ if (auto *VD = dyn_cast_or_null<VarDecl>(
+ ExprEvalContexts.back().ManglingContextDecl)) {
+ if (VD->isConstexpr() ||
+ (VD->isStaticDataMember() && VD->isFirstDecl() && !VD->isInline()))
+ return false;
+ // FIXME: For any other kind of variable, we should build a CFG for its
+ // initializer and check whether the context in question is reachable.
+ }
+
+ Diag(Loc, PD);
+ return true;
+}
+
/// Emit a diagnostic that describes an effect on the run-time behavior
/// of the program being compiled.
///
@@ -18928,28 +18960,7 @@
case ExpressionEvaluationContext::PotentiallyEvaluated:
case ExpressionEvaluationContext::PotentiallyEvaluatedIfUsed:
- if (!Stmts.empty() && getCurFunctionOrMethodDecl()) {
- FunctionScopes.back()->PossiblyUnreachableDiags.
- push_back(sema::PossiblyUnreachableDiag(PD, Loc, Stmts));
- return true;
- }
-
- // The initializer of a constexpr variable or of the first declaration of a
- // static data member is not syntactically a constant evaluated constant,
- // but nonetheless is always required to be a constant expression, so we
- // can skip diagnosing.
- // FIXME: Using the mangling context here is a hack.
- if (auto *VD = dyn_cast_or_null<VarDecl>(
- ExprEvalContexts.back().ManglingContextDecl)) {
- if (VD->isConstexpr() ||
- (VD->isStaticDataMember() && VD->isFirstDecl() && !VD->isInline()))
- break;
- // FIXME: For any other kind of variable, we should build a CFG for its
- // initializer and check whether the context in question is reachable.
- }
-
- Diag(Loc, PD);
- return true;
+ return DiagIfReachable(Loc, Stmts, PD);
}
return false;
Index: clang/include/clang/Sema/Sema.h
===================================================================
--- clang/include/clang/Sema/Sema.h
+++ clang/include/clang/Sema/Sema.h
@@ -4896,7 +4896,7 @@
/// DiagnoseUnusedExprResult - If the statement passed in is an expression
/// whose result is unused, warn.
- void DiagnoseUnusedExprResult(const Stmt *S);
+ void DiagnoseUnusedExprResult(const Stmt *S, unsigned DiagID);
void DiagnoseUnusedNestedTypedefs(const RecordDecl *D);
void DiagnoseUnusedDecl(const NamedDecl *ND);
@@ -5102,6 +5102,16 @@
/// conversion.
ExprResult tryConvertExprToType(Expr *E, QualType Ty);
+ /// Conditionally issue a diagnostic based on the statement's reachability
+ /// analysis evaluation context.
+ ///
+ /// \param Statement If Statement is non-null, delay reporting the
+ /// diagnostic until the function body is parsed, and then do a basic
+ /// reachability analysis to determine if the statement is reachable.
+ /// If it is unreachable, the diagnostic will not be emitted.
+ bool DiagIfReachable(SourceLocation Loc, ArrayRef<const Stmt *> Stmts,
+ const PartialDiagnostic &PD);
+
/// Conditionally issue a diagnostic based on the current
/// evaluation context.
///
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -8562,6 +8562,9 @@
"'__builtin_choose_expr' requires a constant expression">;
def warn_unused_expr : Warning<"expression result unused">,
InGroup<UnusedValue>;
+def warn_unused_comma_left_operand : Warning<
+ "left operand of comma operator has no effect">,
+ InGroup<UnusedValue>;
def warn_unused_voidptr : Warning<
"expression result unused; should this cast be to 'void'?">,
InGroup<UnusedValue>;
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